Nivalenol disrupts mitochondria functions during porcine oocyte meiotic maturation.

Oocyte maturation is important for fertility in mammals, since the quality of oocytes directly affects fertilization, embryo attachment and survival. Nivalenol is widely present in nature as a common toxin that contaminates grain and feed, and it has been reported to cause acute toxicity, immunotoxicity, reproductive toxicity and carcinogenic effects. In this study, we explored the impact of nivalenol on the porcine oocyte maturation and its possible mechanisms. The extrusion of the first polar body was significantly inhibited after incubating oocytes with nivalenol. Meanwhile, nivalenol exposure led to the abnormal distribution of mitochondria, aberrant calcium concentration and the reduction of membrane potential caused a significant decrease in the capacity of mitochondria to generate ATP. In addition, nivalenol induced oxidative stress, and the level of ROS was significantly increased in the nivalenol-treated group, which was confirmed by the perturbation of oxidative stress-related genes. We found that nivalenol-treated oocytes showed positive Annexin-V and γH2A.X signals, indicating the occurrence of apoptosis and DNA damage. In all, our data suggest that nivalenol disrupted porcine oocyte maturation through its effects on mitochondria-related oxidative stress, apoptosis and DNA damage.

ß-catenin expression in rat neovascularized cornea after alkali burn.

AIM: To investigate the expression of ß-catenin in cornea after alkali burn and explore its role in cornea neovascularization (CNV). METHODS: CNV model was established by putting filter paper with the size of 3.0mm in diameter immersed in 1mol/L NaOH solution on the left cornea of rat for 20 seconds. Twenty-five Sprague Dawley rats were randomly divided into 5 groups: post-operation 1-, 4-, 7-, 14- and 21-day groups while the right eyes as normal control group. The expression level of ß-catenin protein, mRNA and VEGF were determined at the 1(st), 4(th), 7(th), 14(th) and 21(st) day following the establishment of model by RT-PCR and immunohistochemical technique. RESULTS: No expression of ß-catenin immunoreactivity was detected in normal cornea. The expressions of ß-catenin and VEGF both reached the peak at the 4(th) and 7(th) day and gradually decreased to near baseline 21 days later. Alteration of ß-catenin and VEGF levels showed a significant positive correlation (r=0.855, P<0.05). CONCLUSION: The levels of ß-catenin are markedly related to inflammatory CNV in rat cornea after alkali burn.